CASP3 and lung cancer: To determine whether the effect of low-dose triptolide in sensitizing lung cancer cells to cisplatin treatment is limited to HTB182 and A549 lung tumor cells and if this effect also exists in other lung tumor cells, we further studied the effect of low-dose triptolide on cisplatin-induced caspase-3 activation in CRL5810 and CRL5922 lung tumor cells and a lower-dose triptolide (1 ng/ml) was used in the study (Fig. 2b).